It is known to provide a communications network, comprising nodes and communications links between the nodes, in which redundancy is provided for maintaining at least some communications among the nodes in the event of failures in the network. For example, in the case of an optical communications network in which optical fibers, which may carry WDM (wavelength division multiplexed) optical signals, provide communications links among optical nodes of the network, protection switching of communications against a failure in the network, for example due to a fiber cut or a node failure, can be provided by re-routing the optical signals via different fibers provided redundantly for this purpose.
Whether or not such a communications network includes such protection switching for its data or user traffic, it must also be set up and arranged to carry necessary non-user or control traffic, for example for administration and network management purposes. To this end, it is known for a network operator to engineer and manually configure or provision the communications network to provide for the necessary control traffic communications. As indicated above, the control traffic can use bandwidth of the same communication links as are used by the data or user traffic, and/or dedicated control traffic paths which are not used for data. The control traffic paths can be considered as a control network which is overlaid on the data or user traffic paths and constitutes a subset of the communications network.
Manual provisioning of the control network takes time and is prone to errors, and these factors become increasingly significant with increasing complexity of the communications network. In addition, in the event of a fault in the communications network, the control traffic of such a manually provisioned control network may not be protected by any protection switching or redundancy that is provided.
Consequently, a need exists for an improved method of providing control communications in communications networks, and consequently improved communications networks.